day I had a rare day off with no pressing demands and decided
to do a little hunting for amoebae. I made the rounds of my three
favorite ponds, sampling the waters and the bottom sediments.
Returning home I settled in with the sample jars full of prospects
and my microscope at the ready, looking forward to an afternoon's
leisurely hunt. Three hours and several sample changes later my
leisurely afternoon turned into an afternoon full of frustration.
Not an amoeba to be found!
one of my trips to the kitchen to wash a microscope slide and
cover slip, for yet another fruitless search, I noticed my wife
had opened the kitchen drapes. Sitting on the kitchen windowsill
is a small flower vase containing a section of bamboo rooting
in water. The sunlight coming through the kitchen window gave
the rooting water an enticing golden hue. Stubbornly, I kept hunting
through the water samples I had already gathered but, all the
while, I kept thinking of that water in the flower vase. Finally,
on a return trip to the kitchen to wash yet another unsuccessful
microscope slide, I carried a plastic pipette and sampled what
little bottom sediment could be sampled in the flower vase.
I wasn't sure of what I was looking at through my 10x objective
lens. The few drops of bamboo water looked fairly sterile; some
large clumps of cyanobacteria here and there and an occasional,
tiny ciliate whizzing through the field of view quicker than I
could make an identification. I encountered the indigestible remains
of a long dead rotifer. I started to get that feeling of discouragement
The most interesting organisms I saw were some long chains of
some sort of cyanobacteria; I can't decide which species, though..
sat staring dully through the binocular head on my microscope
when I realized that one of the large clumps of algae had moved
a considerable distance across the field of view. Huh? I hadn't
fiddled with the stage positioning controls. A closer examination
of the algae clump revealed a single, wide-spreading pseudopod.
In my haste, I failed to recognize the large clumps of algae for
what they were
enormous Thecamoeba!! My quest was
fulfilled. Without a doubt, these are the largest and slowest
moving amoeba I have yet to observe. At lower magnifications one
can hardly tell the amoeba is moving. Higher magnifications reveal
the cytoplasmic flow within the amoeba.
my search with renewed vigor. Higher magnifications revealed a
couple more species of amoeba. Both of these amoeba are considerably
smaller than the Thecamoeba and much faster moving. I would
have mistaken these amoeba as oil drops had not the pseudopodia
been obviously moving.
For some time
now, I have been partially disabled. The collecting trips to nearby
ponds and destinations farther have been reduced drastically.
This day in particular, I had traveled to many ponds within a
few miles of my home and stretched my endurance collecting water
samples. It was quite humbling (as well as a great relief, too)
to have found my quarry in a simple flower vase a few steps from
my workstation. It is quite easy to overlook the obvious.
of the images accompanying this article are single video frame
captures from a simple webcam modified to fit my microscope. You
can view the original video clips at On
Closer Inspection... I enjoy making video clips of the
"micro-critters" I encounter with the webcam but it
does not make a very suitable substitute for a still camera if
still images are to be captured.